1. Technical Field of the Invention
This invention relates to a modular system for seaming (also known as welting, locking or cramping) and a headstock to perform the seaming, aimed at carrying out the union of two or more metal sheets by means of the folding of one of them, which is previously prepared.
2. Prior Art
Seaming headstocks applicable to this technique are known, according to which the joining of the metal parts to each other is carried out by means of a first fold of a flange or lip on one of the two parts over the other and a second fold of this said flange or final fold.
Within this field, the existence of references U.S. Pat Nos. 3,130,770, 3,142,329, FR-A-2,651,699, DE-A-1,452,618, U.S. Pat. No. 5,457,981 and EP-A-0820822 is known, which usually have headstocks connected to structural assemblies, with a structure itself, a base plate, a work table or desk on which the parts to be seamed are placed, and a treader plate.
In the same way, in these references, the headstocks include the work tools for the folding operations, and these headstocks are equipped with two types of movement, one rotation movement by which all the headstock is turned on approaching the work point, and another sliding movement or closer approach of a unit connected to the headstock that holds the tools.
These known headstocks usually also have mechanical stops in their practical embodiment and their way of working is applied to external contours (or profiles) or to internal contours, depending on the cases.
All the techniques shown by the references mentioned above have several disadvantages discussed below.
Reference U.S. Pat. No. 3,130,170 has the disadvantage, among others, that the headstock is not fixed but that it turns in relation to the parts to be worked, which means the occupation of a considerable useful space; it performs the seaming of external contours only; it does not have mechanical work stops nor cradle tool anti-collision safety. The pre-operation tool does not work perpendicular to the part, and it does not have a safety locking system.
Reference U.S. Pat. No. 3,142,329 has the following disadvantages: the headstock has a turning movement in relation to the parts; it does not have mechanical stops; it is not prepared to work with several tools; it performs the seaming of external contours only. The pre-operation tool does not work perpendicular to the part, and it does not have a safety locking system.
Reference FR-A-2,651,699 suffers from the lack of adjustable mechanical stops and it is not a worktop system; it only performs the seaming of external contours.
Reference DE-A-1,452,618 has the disadvantage that the pre-operation is carried out with lateral movement, not perpendicular to the part; it does not have adjustable mechanical stops; it performs the seaming of external contours only and it does not have mechanical stops for cradle tool anti-collision safety or a safety locking system.
Reference US-A-5,457,9S1 is configured with a general headstock that turns in relation to the position of the parts to be worked; it does not have adjustable mechanical stops and it is prepared for seaming external contours only. Besides, it lacks a safety locking system.
Reference EP-A-0,820,822 has a headstock that turns in relation to the position of the parts to be worked; the mechanical stops are integrated into the tool; it is only without mechanical stops for anti-collision safety and it needs items external to the headstock in order to carry out the turning on approach to the part and it lacks a safety locking system.
The fundamental objectives of the present invention are to provide a seaming system with a worktop in which the parts to be seamed remain static, by means of the following:
A fixed headstock provided with slidingxe2x80x94in line movement which the tools have a work-approach movement to the parts to be seamed.
The work tools are located on a common plate and are adjustable.
There are double mechanical stops in all operations.
It is prepared to perform seaming of both external contours and internal contours.
It can perform the seaming in two or three operations, one or two for pre-operation and one for finishing.
It can work with several tools on one single headstock.
It can include several different drive systems to be installed in the headstock.
It includes cradle tool mechanical anti-collision stops.